Tool Review: Bar's Leaks Oil Seal OS-1

Aug. 9, 2021
Reviewed by Lou Fort, lead tech at K.A.R.S. Inc. in Huntingburg, Indiana

Q: What kind of setup was involved before using the product? 

A: The setup is to turn the engine off,  shake the OS-1 well, remove the oil fill cover and pour the OS-1 in per dosage chart. On the next drive, let the engine run for 15 minutes to get a good mix of oil and OS-1. 

Q: How was its packaging? Did it come with any accessories? 

A: The product is in a plastic bottle and it came in a box, which really was not needed. The box is covered with information including a safety notice, warranty, and instructions for getting a $5 rebate. The QR code found on the lid pulls up a link to Bar’s website for the OS-1. The bottle has much of the same information along with usage and a dosage chart. No accessories are included. 

Q: Was there a manual included? If so, was it easy to understand? 

A: There wasn’t a manual but usage and dosage charts are on both the box and the bottle. I didn’t have any trouble understanding any of it. 

Q: What features did you like? 

A: Bar’s Leaks promises it will fix your leak or oil burning problem or your money back. The product is compatible with all types and brands of oil. 

Q: How could the product be improved? 

A: I am not a fan of the dosage recommendation. I rarely see a vehicle that takes just 4.5 quarts at service — this is requiring two bottles to be purchased for most applications. That being said, the bottle should have a measured viewing window on the side so you can see just how much product has been used. 

Q: What types of jobs/repairs did you use this tool for?  

A: My first patient was a 2002 Sienna with leaking seals all over. This one was extremely high mileage, north of 300,000 and had been obviously neglected. It came in for engine noise, not leaks. It was determined that VVT [variable valve timing] noise was present, but the owner declined any further inspection or repairs, so we serviced the engine and added Bar’s Leaks OS-1. By the end of the test drive, the VVT noise had been greatly reduced and the valve cover leaks had stopped — amazing in my opinion. 

Q: Have you used a previous version of this tool? If so, what are some new features? 

A: We have used different brands of magic elixir mixes to help out with all the different issues Bar’s Leaks claims to remedy. We are currently a BG Products shop. I am not much of a chemist so I can’t speak much to the differences in formulation between them all. I do know we get good results from the BG Products and don’t see why we wouldn’t get similar results from the Bar’s Leaks. Like most, Bar’s Leaks recommends usage at every service to continue to see results.  

Q: On a scale of 1 to 10, how would you rate this tool overall? Why? 

A: In all my years in the industry, I have used many Bar’s Leaks products. This newest reformulated one shows how hard Bar’s Leaks is working to improve and keep up with the times. I have read a lot of independent user feedback all of which were high ratings. I would easily give the OS-1 a rating of 10. 

Sponsored Recommendations

Access Carside OEM Repair Data with MOTOR TruSpeed

Now available on all Autel MaxiSYS Ultra Series tools, MOTOR TruSpeed Repair delivers expanded OEM service and repair data within days of being published by

ADAS Case Study: From 10 Calibrations a Month to Over 10 A Day

Originally published by Vehicle Service Pros, March 26, 2024

Ask The Expert: The Basics & Benefits of Bringing ADAS Calibrations In-house

Originally published by Vehicle Service Pros, March 26, 2024

Simplifying the ADAS Opportunity

Originally published by Body Shop Business, February 12, 2024

Voice Your Opinion!

To join the conversation, and become an exclusive member of Vehicle Service Pros, create an account today!